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The closure caused traffic to be reduced from three lanes to one lane near the crest of the grade. The highway normally bottlenecks from three to two lanes as drivers start heading down the north side of the hill.

Jones said that the lane was shut down for work overnight and then remained closed through the day on Wednesday – eventually re-opening at about 6:30 p.m.

Caltrans is working on a $30 million repaving project that will improve the highway from the grade through Atascadero by next year, Jones said.

Workers typically are assigned to weekday late-night shifts or daytime duties - times when traffic is lighter, Jones said.

No work on the roadway is scheduled for the rest of this week and agency officials will be meeting to address the problems on Wednesday and to avoid future backups, Jones said.